As a wireless communication scheme based on carrier sense, for example, IEEE 802.11 is known. In IEEE 802.11, a carrier sense level is uniquely determined for each physical scheme. Thus, according to IEEE 802.11, a plurality of wireless communication apparatuses using the same physical scheme can share the same wireless medium for coexistence.
However, problems may occur if the wireless communication apparatus (referred to as a first wireless communication apparatus in BACKGROUND for convenience) controls the maximum transmission power based on a wireless communication scheme (which is based on carrier sense), for example, IEEE 802.11, to implement close proximity wireless communication with a communication range limited to the order of, for example, several centimeters. Specifically, the equal coexistence between the first wireless communication apparatus and another wireless communication apparatus using the normal maximum transmission power (in BACKGROUND, this wireless communication apparatus is referred to as a second wireless communication apparatus for convenience) is difficult if the second wireless communication apparatus uses the same wireless medium as that for the first wireless communication apparatus and if the first wireless communication apparatus is present within the communication range of the second wireless communication apparatus. The following situation may occur, for example: signals transmitted by the first wireless communication apparatus fail to reach the carrier sense level of the second wireless communication apparatus; however, signals transmitted by the second wireless communication apparatus reach the carrier sense level of the second wireless communication apparatus. Hence, the second wireless communication apparatus can transmit signals regardless of the status of transmissions from the first wireless communication apparatus. However, the first wireless communication apparatus is prevented from transmitting signals depending on the status of transmissions from the second wireless communication apparatus. That is, the first wireless communication apparatus is in an inferior position compared to the second wireless communication apparatus.
Furthermore, the conventional wireless communication scheme based on carrier sense assumes that a plurality of wireless communication apparatuses communicate with one another. Moreover, the wireless communication scheme is designed based on the policy that even if a communication link is degraded, an attempt is made to maintain the communication link. On the other hand, in the close proximity communication, the communication among a plurality of wireless communication apparatuses is not always necessary, and point-to-point communication often has to be only implemented. Moreover, requirement specifications for the close proximity communication include a reduction in the time required until data exchange is started and distinct disconnection of a communication link when a communication distance becomes longer than a certain level.